This invention relates to a reciprocating compressor for gaseous media and, more particularly, to an apertured valve disc arranged between a cylinder and a cylinder head of such a compressor in which a plurality of intake and delivery valve orifices is arranged in the disc about circles concentric with the axis of the cylinder. On the side of the disc which is remote to the cylinder, there is an intake valve strip and on the other side of the disc, there is an outlet valve strip, both of the strips being acted upon by stroke limiters and secured centrally to the disc.
A valve system is known for reciprocating compressors. Flat valve strips can be used to cover only a single valve aperture but it is possible to use a circular or semicircular ring to cover a number of apertures. The ring is usually secured to two links. All known valve systems of this type share, inter alia, the disadvantage that the aperture cross section or valve-gap cross section is very small in relation to the available piston area. Thus, only medium piston speeds of up to approximately 4 meters per second can be utilized. The unit volume which can be delivered from a cylinder of a reciprocating compressor is limited by the available cross-sectional area of the valve gap and the maximum permissible velocity of the medium through the gap. In valves of this type, for example, when the gaseous medium is air, the largest possible flow velocity of the air is 75 meters per second. Higher flow velocities lead to a pressure drop and heating. Consequently, the only way to achieve an appreciable increase to the flow delivery velocity is indirectly by substantially increasing the cross-sectional area to the valve gap. This area is the product of the peripheral length of the gap opening; of the average gap height, i.e., mean strip lift, and the number of apertures. The maximum permissible average lift to the valve strips depends upon the frequency at which the strips are opened and closed and the mass of the strips. In practice, the average strip lift should not exceed 1.5 millimeters where the maximum possible compressor speed is 3000 revolutions per minute and air is the gaseous medium to insure long life of the parts. It is pointless to provide a valve opening diameter greater than 7 millimeters. Consequently, the only way for increasing the total valve-gap area is to increase the number of the valve gaps not enlarge the valve apertures.